700001 is the Pin Code of Telephone Bhawan, Kolkata which is based at Kolkata district, in West Bengal state. PIN is the short form of postal index number and it is the merge of 6 digit number that You can also call Zip Code, Postal Code, and Pin Code, that indicate each post offices with a separate number that is distributed into three units like, Zip Code of Telephone Bhawan is 700001 in which the starting digit means 7 that belong to region of Postal Code means Calcutta and the second digit means 0 that display the sub region and the third means 0 is used as short districts means, Kolkata is the district of Telephone Bhawan and the last three digits means 001 are used to show the Post Offices.